US5030923A - Variable gain amplifier - Google Patents

Variable gain amplifier Download PDF

Info

Publication number
US5030923A
US5030923A US07/437,570 US43757089A US5030923A US 5030923 A US5030923 A US 5030923A US 43757089 A US43757089 A US 43757089A US 5030923 A US5030923 A US 5030923A
Authority
US
United States
Prior art keywords
current
gain
transistors
control
stage amplifying
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US07/437,570
Other languages
English (en)
Inventor
Masashi Arai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sanyo Electric Co Ltd
Original Assignee
Sanyo Electric Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sanyo Electric Co Ltd filed Critical Sanyo Electric Co Ltd
Assigned to SANYO ELECTRIC CO., LTD., reassignment SANYO ELECTRIC CO., LTD., ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ARAI, MASASHI
Application granted granted Critical
Publication of US5030923A publication Critical patent/US5030923A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G3/00—Gain control in amplifiers or frequency changers
    • H03G3/20—Automatic control
    • H03G3/30—Automatic control in amplifiers having semiconductor devices
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03G—CONTROL OF AMPLIFICATION
    • H03G1/00—Details of arrangements for controlling amplification
    • H03G1/0005—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal
    • H03G1/0017—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal the device being at least one of the amplifying solid state elements of the amplifier
    • H03G1/0023—Circuits characterised by the type of controlling devices operated by a controlling current or voltage signal the device being at least one of the amplifying solid state elements of the amplifier in emitter-coupled or cascode amplifiers

Definitions

  • the present invention relates generally to a variable gain amplifiers, and more particularly, to a variable gain amplifier capable of ensuring a wide gain-controllable range.
  • a circuit diagram showing an RDS signal decoder IC is described in an article "Development of Radio Data System Decoder IC's" in page 383-394 of IEEE Transactions on CONSUMER ELECTRONICS, Vol. CE-33, No. 3 issued on Aug. 26, 1987.
  • a variable gain amplifier for making the level of an RDS signal constant is arranged in the RDS signal decoder IC.
  • the above described variable gain amplifier has such a structure as shown in FIG. 3.
  • an input signal Vi to be subjected to gain-control is applied to an input terminal 1 and is then amplified in a first stage amplifying portion 4 including first and second transistors 2 and 3.
  • a gain-controlling signal Vc is applied to a control input terminal 5 of the first stage amplifying portion 4. Accordingly, a gain of the first stage amplifying portion 4 becomes to be corresponding to the gain-controlling signal Vc.
  • An output signal V 01 of the first stage amplifying portion 4 is taken-out from collectors of the first and second transistors 2 and 3 which are double- ended, being applied to a subsequent stage amplifying portion 6.
  • the output signal V 01 is further amplified in the subsequent stage portion 6 and then, provided to an output terminal 7.
  • the gain G l of the first stage amplifying portion 4 is as follows: ##EQU1## where K is the Boltzmann constant, T is the absolute temperature, and q is the charge on electrons.
  • V O is an output voltage obtained at the output terminal 7.
  • a total gain G of the circuit shown in FIG. 3 is as follows: ##EQU3##
  • R E >>2KT/qI l because 2KT/qI l is an internal resistance of the emitter of the transistor. Accordingly, the total gain G is approximately proportional to I 2 /I l . Consequently, if the control signal Vc applied to the control input terminal 5 is varied, the current Il is changed in response thereto , so that the total gain G is changed. Therefore, the circuit shown in FIG. 3 can be used as a variable gain amplifier.
  • a maximum gain of the variable gain amplifier shown in FIG. 3 is determined by the resistance value R E of the resistor 8. The smaller the above resistance value R E is, the larger the maximum gain can be.
  • an input dynamic range of the above described variable gain amplifier shown in FIG. 3 is determined by a product of the resistance value R E of the resistor 8 and the current I l flowing through the constant-current transistors 9 and 10, i.e., R E .I l .
  • a gain-controllable range of the variable gain amplifier shown in FIG. 3 is determined by an inherent maximum current value being dependent on resistance components of diodes 13 and 14, saturation of the first and second transistors 2 and 3 and etc.
  • the resistor 8 is associated with all characteristics such as a maximum gain, an input dynamic range, and an gain-controllable range.
  • characteristics such as a maximum gain, an input dynamic range, and an gain-controllable range.
  • a direction of a change in value of the resistor 8 and a direction of improvements in the above characteristics do not necessarily coincide with each other. Accordingly, it is very difficult to select a resistance value at which the above characteristics are all the best.
  • a principal object of the present invention is to provide a novel variable gain amplifier.
  • Another object of the present invention is to provide a variable gain amplifier having a wider range wherein a gain can be controlled or varied.
  • the other object of the present invention is to provide a variable gain amplifier capable of being easily designed.
  • a variable gain amplifier in accordance with the present invention comprises a first stage amplifying portion including a pair of transistors and diodes arranged as loads of the pair of transistors; a subsequent stage amplifying portion for amplifying an output signal of the first stage amplifying portion; a reference current generating portion for generating a reference current; a control current generating portion for generating a control current which is N times the reference current to supply the same to collectors of the pair of transistors; a current sinking portion for sinking currents flowing through the diodes; and a control portion for controlling values of the reference current and a sunk current in response to a level of a gain-controlling signal.
  • a maximum current is supplied to the collectors of the pair of transistors from the control current generating portion while a level of an input signal is small. Consequently, a gain of a first stage amplifying portion becomes maximum.
  • the control current of the control current generating portion is decreased, so that the gain of the first stage amplifying portion is decreased.
  • the current sinking portion has not started to operate yet.
  • the reference current of the reference current generating portion becomes zero and then, the current sinking portion starts to operate. Accordingly, currents flowing through diodes serving as loads are increased, so that the gain of the first stage amplifying portion is further decreased.
  • the gain-control is exercised by means of combination of first gain control using the reference current generating portion and the control current generating portion and second gain control using the current sinking portion, the gain-controllable range can be enlarged.
  • the maximum gain can be set by the reference current generating portion and the input dynamic range can be set by a resistor connected between the emitters of the pair of transistors in the first stage amplifying portion, it is possible to provide a variable gain amplifier which can be easily designed.
  • FIG. 1 is a circuit diagram showing a variable gain amplifier in accordance with an embodiment of the present invention.
  • FIG. 2 is a circuit diagram showing one example of a control current generating portion in FIG. 1 embodiment.
  • FIG. 3 is a circuit diagram showing a conventional variable gain amplifier.
  • FIG. 1 is a circuit diagram showing a variable gain amplifier in accordance with an embodiment of the present invention.
  • a first stage amplifying portion 15 includes an input terminal 16 to which an input signal to be controlled is applied, first and second transistors 17 and 18, a resistor 19 connected between emitters of the first and second transistors 17 and 18 to set an input dynamic range, first and second constant-current circuits 20 and 21 constituting emitter current paths of the above first and second transistors 17 and 18, and first and second diodes 22 and 23 connected to collectors of the first and second transistors 17 and 18.
  • the first and second diodes 22 and 23 serve as loads for the first and second transistors 17 and 18, respectively.
  • a subsequent stage amplifying portion 24 includes third and fourth transistors 25 and 26 differentially connected to each other and a current mirror circuit 27 arranged as a collector load of the third and fourth transistors 25 and 26.
  • a load resistor 28 is connected to an output terminal 29 connected to a collector of the above fourth transistor 26.
  • a reference current generating portion 30 includes fifth and sixth transistors 31 and 32 differentially connected to each other to generate a reference current.
  • control current generating portion 33 having a current mirror circuit configuration for generating a current which is N times (N ⁇ 1) the above reference current.
  • the control current generating portion 33 includes three transistors 33a, 33b and 33c connected in parallel with each other.
  • Collectors of the transistors 33a and 33b are connected to the collectors of the first and second transistors 17 and 18 and thus cathodes of the first and second diodes 22 and 23.
  • Emitters of the transistors 33a and 33b are commonly connected to a voltage source Vcc through resistors 33d and 33e, respectively.
  • a collector of the transistor 33c is connected to the collector of the transistor 31 and a base of the transistor 33f which is connected between the bases of three transistors 33a-33c and the ground.
  • An emitter of the transistor 33c is connected to the above voltage source Vcc through a resistor 33g.
  • control current generating portion 33 in accordance with the teachings taught by the article "Integrated linear basic circuits", page 1-12 of Philips Technical Review, Vol. 32, 1971, No. 1, by making each of the emitter resistors 33d and 33i e N times the emitter resistor 33g, an output current becomes N times the collector current of the transistor 31.
  • a current sinking portion 34 includes seventh and eighth transistors 35 and 36 for sinking currents flowing through the above first and second diodes 22 and 23 and a voltage source 37 for applying an offset voltage to bases of the seventh and eight transistors 35 and 36.
  • a control portion 39 includes a ninth transistor 40 having its base receiving a gain-controlling signal for controlling the above reference current generating portion 30 and the above current sinking portion 34 by a collector voltage of the ninth transistor 40.
  • the input signal applied to the input terminal 16 is amplified in the first stage amplifying portion 15 and then, is further amplified in the subsequent stage amplifying portion 24, to generate an amplified output signal at the output terminal 29.
  • a gain-controlling signal Vc for gain-controlling applied to a control terminal 41 becomes small, so that the ninth transistor 40 is turned- off. Consequently, a base voltage of the fifth transistor 31 constituting the reference current generating portion 30 becomes higher than a base voltage of the sixth transistor 32 by a voltage component of the voltage source 37 (approximately 200 mV), so that the fifth transistor 31 is turned-on while the sixth transistor 32 is turned-off. Accordingly, the output current of the reference current generating portion 30 becomes equal in value to a current I l flowing through a constant-current circuit 42. The above output current is multiplied by N in the control current generating portion 33, being supplied to the collectors of the first and second transistors 17 and 18.
  • the gain of the first stage amplifying portion 15 is determined by the currents flowing through the above first and second diodes 22 and 23.
  • the control current generating portion 33 is provided in FIG. 1 circuit, portions of the collector currents of the first and second transistors 17 and 18 are respectively forced to be supplied from the control current generating portion 33, so that the currents flowing through the first and second diodes 22 and 23 are reduced. Accordingly, the gain of the first stage amplifying portion 15 is increased.
  • the ninth transistor 40 is turned-off, so that the collector current of the fifth transistor 31 becomes I l and the output control current of the control current generating portion 33 becomes N.I l . Accordingly, the gain of the first stage amplifying portion 15 becomes maximum.
  • the collector current of the fifth transistor 31 is decreased from I l in accordance with the gain-controlling signal Vc.
  • the fifth transistor 31 is turned-off while the sixth transistor 32 is turned-on, so that the collector current of the above fifth transistor 31, that is, the output current of the reference current generating portion 30 becomes zero. Accordingly, the output control current of the control current generating portion 33 also becomes zero. Therefore, the collector currents flowing through the first and second transistors 17 and 18 respectively become equal to the currents flowing through the first and second diodes 22 and 23. Accordingly, the gain of the first stage amplifying portion 15 becomes a small predetermined value.
  • the collector voltage of the ninth transistor 40 at that time corresponds to the value of a voltage source 43.
  • V 1 is a voltage of the voltage source 37
  • V 2 is a voltage of the voltage source 43
  • VBE is a base-emitter voltage of each of the seventh and eighth transistors 35 and 36.
  • the output currents of the first and second diodes 22 and 23 respectively become equal to a summed current of the collector currents of the first and second transistors 17 and 18 and the collector currents of the seventh and eighth transistors 35 and 36. Accordingly, the gain of the first stage amplifying portion 15 is further decreased.
  • the gain of the first stage amplifying portion 15 is a value corresponding to a control current determined by a reference current I 2 equal to the current Il flowing through the constant-current circuit 42 and the current ratio N of the control current generating portion 33 while the input signal is small.
  • the gain is decreased if the above reference current I 2 is decreased to M I l with the increase in the input signal.
  • a non-controlled state occurs where the gain is determined by currents flowing through the constant-current circuits 20 and 21 if the above reference current I 2 becomes zero.
  • the gain is further decreased depending on a sunk current of the current sinking portion 34 if the input signal is further increased.
  • variable gain amplifier as shown in FIG. 1 can significantly enlarge the gain controllable range.
  • maximum gain is determined by the maximum control current of the control current generating portion 33, that is, the current I 1 flowing through the constant-current circuit 42 in the reference current generating portion 30 and the current ratio N and can be arbitrarily set.
  • the input dynamic range of the variable gain amplifier shown in FIG. 1 is determined by the currents flowing through the constant-current circuits 20 and 21 and the resistor 19. Unlike the conventional variable gain amplifier, however, the value of the above described resistor 19 need not be considered with reference to setting of the gain control range and the maximum gain. Consequently, the input dynamic range can be set to such a value that it is enlarged, that is, a relatively large value.

Landscapes

  • Control Of Amplification And Gain Control (AREA)
  • Amplifiers (AREA)
US07/437,570 1988-11-18 1989-11-17 Variable gain amplifier Expired - Lifetime US5030923A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP63292858A JPH0666614B2 (ja) 1988-11-18 1988-11-18 利得制御増幅回路
JP63-292858 1988-11-18

Publications (1)

Publication Number Publication Date
US5030923A true US5030923A (en) 1991-07-09

Family

ID=17787283

Family Applications (1)

Application Number Title Priority Date Filing Date
US07/437,570 Expired - Lifetime US5030923A (en) 1988-11-18 1989-11-17 Variable gain amplifier

Country Status (5)

Country Link
US (1) US5030923A (ko)
EP (1) EP0369469B1 (ko)
JP (1) JPH0666614B2 (ko)
KR (1) KR970004617B1 (ko)
DE (1) DE68918667T2 (ko)

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5574714A (en) * 1993-11-22 1996-11-12 Sanyo Electric Co., Ltd. Amplifier with peak and bottom signal level shifting control
US5719518A (en) * 1992-10-22 1998-02-17 Nokia Technology Gmbh Variable electronic resistor having parallel phase-inverted variable semiconductor channels with common control input and current-to-voltage converters
US5900782A (en) * 1996-04-23 1999-05-04 Alps Electric Co., Ltd. AGC voltage correction circuit
WO1999063657A1 (en) * 1998-06-02 1999-12-09 Maxim Integrated Products, Inc. Linear quad variable gain amplifier and method for implementing same
US6798290B2 (en) * 2001-08-31 2004-09-28 Sequoia Communications Translinear variable gain amplifier
US20070205200A1 (en) * 2006-03-02 2007-09-06 Brain Box Concepts Soap bar holder and method of supporting a soap bar
US7412213B1 (en) 2001-07-23 2008-08-12 Sequoia Communications Envelope limiting for polar modulators
US7479815B1 (en) 2005-03-01 2009-01-20 Sequoia Communications PLL with dual edge sensitivity
US7489916B1 (en) 2002-06-04 2009-02-10 Sequoia Communications Direct down-conversion mixer architecture
US7496338B1 (en) 2003-12-29 2009-02-24 Sequoia Communications Multi-segment gain control system
US7522017B1 (en) 2004-04-21 2009-04-21 Sequoia Communications High-Q integrated RF filters
US7522005B1 (en) 2006-07-28 2009-04-21 Sequoia Communications KFM frequency tracking system using an analog correlator
US7548122B1 (en) 2005-03-01 2009-06-16 Sequoia Communications PLL with switched parameters
US7587179B1 (en) 2001-10-04 2009-09-08 Sequoia Communications Direct synthesis transmitter
US7595626B1 (en) 2005-05-05 2009-09-29 Sequoia Communications System for matched and isolated references
US7609118B1 (en) 2003-12-29 2009-10-27 Sequoia Communications Phase-locked loop calibration system
US7672648B1 (en) 2004-06-26 2010-03-02 Quintics Holdings System for linear amplitude modulation
US7675379B1 (en) 2005-03-05 2010-03-09 Quintics Holdings Linear wideband phase modulation system
US7679468B1 (en) 2006-07-28 2010-03-16 Quintic Holdings KFM frequency tracking system using a digital correlator
US7894545B1 (en) 2006-08-14 2011-02-22 Quintic Holdings Time alignment of polar transmitter
US7920033B1 (en) 2006-09-28 2011-04-05 Groe John B Systems and methods for frequency modulation adjustment
US7974374B2 (en) 2006-05-16 2011-07-05 Quintic Holdings Multi-mode VCO for direct FM systems

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2690599B2 (ja) * 1990-05-18 1997-12-10 日本電気アイシーマイコンシステム株式会社 可変利得増幅器
US5432477A (en) * 1992-07-31 1995-07-11 Sony Corporation Wide frequency range amplifier apparatus
EP0948132B1 (en) * 1998-03-31 2004-05-26 STMicroelectronics S.r.l. Amplifier with programmable gain and input linearity usable in high-frequency lines

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4101841A (en) * 1976-09-03 1978-07-18 Hitachi, Ltd. Gain control circuit
US4134078A (en) * 1976-08-11 1979-01-09 Hitachi, Ltd. Gain control circuit

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3974438A (en) * 1973-09-13 1976-08-10 Rca Corporation Apparatus for indicating over-current condition in a transistor amplifier
JPS5696516A (en) * 1979-12-28 1981-08-04 Matsushita Electric Ind Co Ltd Gain adjusting circuit
JPS58115910A (ja) * 1981-12-29 1983-07-09 Matsushita Electric Ind Co Ltd 制御回路
JPS6190507A (ja) * 1984-10-09 1986-05-08 Toshiba Corp 自動利得制御回路

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4134078A (en) * 1976-08-11 1979-01-09 Hitachi, Ltd. Gain control circuit
US4101841A (en) * 1976-09-03 1978-07-18 Hitachi, Ltd. Gain control circuit

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
"Development of Radio Data System Decoder IC's", Ogawa et al., IEEE Transactions on Consumer Electronics, vol. CE-33, No. 3, Aug., 1987, pp. 383-394.
"Integrated Linear Basic Circuits", van Kessel et al., Philips Technical Review, vol. 32, 1971, No. 1, pp. 1-12 and 32.
Development of Radio Data System Decoder IC s , Ogawa et al., IEEE Transactions on Consumer Electronics, vol. CE 33, No. 3, Aug., 1987, pp. 383 394. *
Integrated Linear Basic Circuits , van Kessel et al., Philips Technical Review, vol. 32, 1971, No. 1, pp. 1 12 and 32. *

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5719518A (en) * 1992-10-22 1998-02-17 Nokia Technology Gmbh Variable electronic resistor having parallel phase-inverted variable semiconductor channels with common control input and current-to-voltage converters
US5574714A (en) * 1993-11-22 1996-11-12 Sanyo Electric Co., Ltd. Amplifier with peak and bottom signal level shifting control
US5900782A (en) * 1996-04-23 1999-05-04 Alps Electric Co., Ltd. AGC voltage correction circuit
WO1999063657A1 (en) * 1998-06-02 1999-12-09 Maxim Integrated Products, Inc. Linear quad variable gain amplifier and method for implementing same
US6091275A (en) * 1998-06-02 2000-07-18 Maxim Integrated Products, Inc. Linear quad variable gain amplifier and method for implementing same
US7412213B1 (en) 2001-07-23 2008-08-12 Sequoia Communications Envelope limiting for polar modulators
US6798290B2 (en) * 2001-08-31 2004-09-28 Sequoia Communications Translinear variable gain amplifier
US20050099232A1 (en) * 2001-08-31 2005-05-12 Groe John B. Translinear variable gain amplifier
US7132889B2 (en) * 2001-08-31 2006-11-07 Sequoia Communications Translinear variable gain amplifier
US7587179B1 (en) 2001-10-04 2009-09-08 Sequoia Communications Direct synthesis transmitter
US7489916B1 (en) 2002-06-04 2009-02-10 Sequoia Communications Direct down-conversion mixer architecture
US7496338B1 (en) 2003-12-29 2009-02-24 Sequoia Communications Multi-segment gain control system
US7609118B1 (en) 2003-12-29 2009-10-27 Sequoia Communications Phase-locked loop calibration system
US7522017B1 (en) 2004-04-21 2009-04-21 Sequoia Communications High-Q integrated RF filters
US7672648B1 (en) 2004-06-26 2010-03-02 Quintics Holdings System for linear amplitude modulation
US7548122B1 (en) 2005-03-01 2009-06-16 Sequoia Communications PLL with switched parameters
US7479815B1 (en) 2005-03-01 2009-01-20 Sequoia Communications PLL with dual edge sensitivity
US7675379B1 (en) 2005-03-05 2010-03-09 Quintics Holdings Linear wideband phase modulation system
US7595626B1 (en) 2005-05-05 2009-09-29 Sequoia Communications System for matched and isolated references
US20070205200A1 (en) * 2006-03-02 2007-09-06 Brain Box Concepts Soap bar holder and method of supporting a soap bar
US7974374B2 (en) 2006-05-16 2011-07-05 Quintic Holdings Multi-mode VCO for direct FM systems
US7522005B1 (en) 2006-07-28 2009-04-21 Sequoia Communications KFM frequency tracking system using an analog correlator
US7679468B1 (en) 2006-07-28 2010-03-16 Quintic Holdings KFM frequency tracking system using a digital correlator
US7894545B1 (en) 2006-08-14 2011-02-22 Quintic Holdings Time alignment of polar transmitter
US7920033B1 (en) 2006-09-28 2011-04-05 Groe John B Systems and methods for frequency modulation adjustment

Also Published As

Publication number Publication date
KR970004617B1 (ko) 1997-03-29
EP0369469A3 (en) 1991-07-03
JPH02137509A (ja) 1990-05-25
DE68918667T2 (de) 1995-05-18
JPH0666614B2 (ja) 1994-08-24
EP0369469B1 (en) 1994-10-05
KR900008769A (ko) 1990-06-04
DE68918667D1 (de) 1994-11-10
EP0369469A2 (en) 1990-05-23

Similar Documents

Publication Publication Date Title
US5030923A (en) Variable gain amplifier
US5668468A (en) Common mode stabilizing circuit and method
JP4291354B2 (ja) デシベル−線形出力電圧を有する増幅段
US6583667B1 (en) High frequency CMOS differential amplifiers with fully compensated linear-in-dB variable gain characteristic
KR20010020410A (ko) 선형성 및 대역폭이 개선된 가변 이득 증폭기
US4065725A (en) Gain control circuit
JPH1127068A (ja) 利得制御増幅器及びその制御方法
US5150076A (en) Emitter-grounded amplifier circuit with bias circuit
EP0196906B1 (en) Automatic gain control detection circuit
US4516081A (en) Voltage controlled variable gain circuit
US6445251B1 (en) Variable gain amplifier with high linearity and low noise
US6020786A (en) Temperature compensation for variable gain amplifiers
US4219781A (en) Transistor amplifier circuit
KR100732068B1 (ko) 지수적인 선형성을 갖는 가변 이득 증폭기
US5442311A (en) System and method for controlling a gain circuit
US5936391A (en) Partially temperature compensated low noise voltage reference
US5352944A (en) Apparatus and method for producing a temperature-independent current signal in an automatic gain control circuit
US5038114A (en) Current amplifier
US5278518A (en) Amplifying circuit with exponential gain control
US4733161A (en) Constant current source circuit
US4926137A (en) Transistor amplifier for outputting a voltage which is higher than a breakdown voltage of the transistor
US4638239A (en) Reference voltage generating circuit
EP0426120B1 (en) Amplification circuit with improved linearity
US5977760A (en) Bipolar operational transconductance amplifier and output circuit used therefor
US6292056B1 (en) Differential amplifier with adjustable common mode output voltage

Legal Events

Date Code Title Description
AS Assignment

Owner name: SANYO ELECTRIC CO., LTD.,, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ARAI, MASASHI;REEL/FRAME:005199/0768

Effective date: 19891211

STCF Information on status: patent grant

Free format text: PATENTED CASE

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12